Interfaces are wrongly treted as abstract classes in inheritance

<img width="1088" alt="image" src="https://user-images.githubusercontent.com/10419217/188167143-e9b8d442-43e5-4748-a031-c722c11f2ff5.png">

the correct way to implement an interface (and not a base class) would be

```fsharp
interface with
```